1. Field of the Invention
The present invention relates to delivery systems and methods useful for the treatment of neoplastic diseases, and to combinations of treatments useful for the treatment of neoplastic diseases.
2. Description of Related Art
Two important events in the cell division cycle are the duplication of the chromosomal DNA and the separation of the duplicated chromosomes. These events occur in two discrete phases: the synthetic phase (S-phase) and the mitotic phase (M-phase), which are separated from each other by distinct gaps in time, gap 1 (G1) and gap 2 (G2). The proper coordination of these events is achieved by checkpoint pathways that delay the progression of the cell cycle when proper completion of one phase is disrupted by physical damage or other means. Under normal circumstances, if the extent of damage is irreparable, most cells initiate a sequence of biochemical events leading to programmed cell death or apoptosis. Deregulation in any one or more of these checkpoint mechanisms sometimes leads to genetic instability which is a primary step for a tumor to evolve into invasive malignant state. The chemotherapeutic management of various cancers is achieved by drugs that block either the S-phase, the M-phase, or that block regulatory or metabolic pathways impinging upon the cell cycle machinery.
For example, some drugs affect the functions or structures of DNA or RNA, others interfere with enzymes involved in folate, purine, or pyrimidine metabolism, or the function of mitotic spindles. Anti-mitotic drugs such as vinica akaloids and taxoids can arrest cells in M-phase by interacting with mitotic spindle components, microtubules. Microtubules are one of the major filamentous components of the cytoskeleton, and, together with actin and intermediate filaments, they organize the cellular cytoplasm. In interphase cells, a dynamic radial array of microtubules emanates from the centrosome at the cell center. In this array, the fast growing and fast shrinking plus ends of microtubules project distally from the center.
During mitosis, the duplicated centrosomes nucleate assembly of much more dynamic and more numerous polymers as they move apart to form the opposite poles of the mitotic spindle. The increased dynamics and number of microtubules enhance the chance-encounter of growing microtubules with the primary construction of the duplicated chromatid pairs. Upon attaching to microtubules, chromosomes undergo a series of movements eventually leading to their conversion and final assembly at the mid-plate during metaphase. The onset of the next event in mitosis, the anaphase, is delayed until each of the chromatid pairs is assembled at the metaphase mid-plate and proper tension is generated on the attached sister chromatids.
Dynamic assembly or disassembly of microtubules is required for the morphogenesis of mitotic spindle. Accordingly, small organic molecules that modulate the dynamics of microtubules primarily because some of the microtubule interacting agents are useful for chemotherapeutic management of certain kinds of tumors. There are two classes of these anti-microtubule agents: those that prevent the assembly of tubulin, and those that promote the assembly of tubulin. A prototypic example of a potent assembly inhibitor is colchicine. Others are analogs of colchicine such as podophyllotoxin, MTC [(2-methoxy-5-(2,3,4-trimethoxyphenyl)-2,4,6-cycloheptatrien-1one)], TCB (2,3,4-trimethoxy-4xe2x80x2-carbomethoxy-1, 1xe2x80x2-biphenyl) and TKB (2,3,4-trimethoxy-4xe2x80x2-acetyl-1,1xe2x80x2-biphenyl), and vinica akaloids. Taxol and its analogs represent a class of compounds that promote the assembly of microtubules. It is now clear that although all of these microtubule drugs prevent cell division, only a select few have been useful clinically. In addition, there are differences regarding the toxicity and the efficacy of these drugs for distinct classes of tumors.
Applicants have discovered that the antitussive noscapine and its derivatives are useful in the treatment of neoplastic diseases. Noscapine is used as an antitussive drug and has low toxicity in humans. Noscapine arrests mammalian cells at mitosis, causes apoptosis in cycling cells, and has potent antitumor activity. Noscapine is an alkaloid from opium, and is readily available as a commercial byproduct in the commercial production of prescription opiates. Applicants have unexpectedly discovered that noscapine promotes assembly of tubulin subunits.
Applicants have synthesized derivatives of noscapine, a known antitussive having low toxicity in humans, and have shown they promote assembly of tubulin subunits, a characteristic suitable for the treatment of tumors and various neoplastic diseases.
In one embodiment of the invention, Applicants provide delivery systems and methods for the treatment of neoplastic diseases. For example, one delivery system according to an embodiment of this invention comprises a composition comprising noscapine or a noscapine derivative and a controlled-release mechanism to enhance delivery of the composition. In a further embodiment, Applicants provide a method for the treatment of neoplastic diseases wherein noscapine and its derivatives can be delivered in combination with another tumor therapy for the treatment or prevention of tumors.
One embodiment of the present invention relates to systems and methods for the treatment of neoplastic diseases, comprising a composition comprising a compound of the formula 
wherein:
1. A is 
and W is C1-6 alkyl; 
and forms a six membered ring
with B, said ring containing one nitrogen;
Y is
(a) C1-6 alkyl, or H;
(b) C(O)xe2x80x94C1-6 alkyl; 
wherein Z is C1-6 alkyl or O-C1-6 alkyl or O-C1-6 alkyl;
(d) aryl; or
(e) heterocycle;
B is a single bond, OH or halo;
C is xe2x80x94OH, xe2x80x94CH2xe2x80x94, xe2x80x94Oxe2x80x94, or forms a 5-membered lactone or lactam ring with D; and
D is:
(i) xe2x80x94OH, xe2x80x94CH2-halo, xe2x80x94CH(O)xe2x80x94, xe2x80x94COOH, xe2x80x94C(O)xe2x80x94Oxe2x80x94C1-6 alkyl, xe2x80x94(CH2)nxe2x80x94,xe2x80x94CHOHxe2x80x94, wherein n is an integer and is 1,2, or 3; or
(ii) forms a 5-membered lactone or lactam ring with C;
E is xe2x80x94H or xe2x80x94CH3; and
F is xe2x80x94OH or xe2x80x94OCH3,
or pharmaceutically acceptable salts thereof, and a controlled-release mechanism, whereby the delivery system enhances the delivery of the composition to a patient in need thereof.
Examples of controlled-release mechanisms suitable for use in the delivery system of the invention include, but are not limited to implantable devices, delivery pumps, wafers, gels, lotions, topical applications, and combinations thereof. Other examples of controlled-release mechanisms include but are not limited to controlled-release formulations comprising a modified compound. For the purposes of this document, xe2x80x9cmodifiedxe2x80x9d means chemically changed, associated with, combined with, mixed with, delivered with, encapsulated by, caged, protected, lipidized, structurally modified to enhance stability, glycosylized, combined with nutrient transporters, used as a prodrug, incorporated with vector-based strategies, cationization, polymer conjugation, or combinations thereof, such that the compounds is at least partially altered from the above structure.
For example, controlled-release mechanisms may include but are not limited to the compound being caged, protected, or otherwise modified forms of the compound, such as modification to enhance its permeability through a patient""s blood-brain barrier, modifications to the compound for tumor targeting purposes, and combinations thereof.
An example of a preferred compound that may be used in the delivery systems or methods of this invention is: 
or pharmaceutically acceptable salt thereof.
Another embodiment of the present invention also relates to a method for the treatment of neoplastic diseases, comprising administering to a mammal in need of such treatment an effective amount of a composition comprising a compound of the formula 
wherein:
A is 
and W is C1-6 alkyl; 
and forms a six membered ring
with B, said ring containing one nitrogen;
Y is
(a) C1-6 alkyl, or H;
(b) C(O)xe2x80x94C1-6 alkyl; 
wherein Z is C1-6 alkyl or Oxe2x80x94C1-6 alkyl;
(d) aryl; or
(c) heterocycle;
B is a single bond, OH or halo;
C is xe2x80x94OH, xe2x80x94CH2xe2x80x94, xe2x80x94Oxe2x80x94, or forms a 5-membered lactone or lactam ring with D; and
D is:
(i) xe2x80x94OH, xe2x80x94CH2-halo, xe2x80x94CH(0)xe2x80x94, xe2x80x94COOH, xe2x80x94C(O)xe2x80x94Oxe2x80x94C1-6 alkyl, xe2x80x94(CH2)nxe2x80x94, xe2x80x94CHOHxe2x80x94, wherein n is an integer and is 1,2, or 3; or
(ii) forms a 5-membered lactone or lactam ring with C;
E is xe2x80x94H or xe2x80x94CH3; and
F is xe2x80x94OH or xe2x80x94OCH3,
or pharmaceutically acceptable salts thereof, in combination with a tumor therapy.
Exemplary tumor therapies include but are not limited to radiation therapy, phototherapy, surgical resection, immunotherapy, vaccination, interferon treatment, chemotherapy, stereotactic surgery, such as Gamma Knife(copyright) surgery, and combinations thereof.
An example of a preferred compound that may be used in the delivery systems or methods of this invention is: 
or pharmaceutically acceptable salts thereof.
Other embodiments of the present invention relate to a method for the treatment of neoplastic diseases, comprising administering the compositions described above via oral delivery, rectal delivery, nasal delivery, parenteral delivery, subcutaneous delivery, intravenous delivery, intramuscular delivery, intraperitoneal delivery, infrasternal injection, infusion, direct tissue injection, topical delivery, intracranial delivery and combinations thereof.
The compounds of the present invention, may have asymmetric centers and occur as racemates, racemic mixtures and as individual diastereomers or enantiomers, with all isomeric forms being included in the present invention.
When any variable (e.g., W, Y, A, B, C, etc.) occurs more than one time in any constituent or in formula I, its definition on each occurrence is independent of its definition at every other occurrence. Also, combinations of substituents and/or variables are permissible only if such combinations result in stable compounds. As used herein except where noted, xe2x80x9calkylxe2x80x9d is intended to include both branched-and straight-chain saturated aliphatic hydrocarbon groups having the specified number of carbon atoms (Me is methyl, Et is ethyl, Pr is propyl, Bu is butyl); xe2x80x9cHaloxe2x80x9d as used herein means fluoro, chloro, bromo and iodo. As used herein, with exceptions as noted, xe2x80x9carylxe2x80x9d is intended to mean phenyl (Ph) or naphthyl.
The term heterocycle or heterocyclic, as used herein except where noted, represents a stable 5-to 7-membered mono-or bicyclic or stable 7-to 10-membered bicyclic heterocyclic ring system any ring of which may be saturated or unsaturated, and which consists of carbon atoms and from one to three heteroatoms selected from the group consisting of N, O and S, and wherein the nitrogen and sulfur heteroatoms may optionally be oxidized, and the nitrogen heteroatom may optionally be quaternized, and including any bicyclic group in which any of the above-defined heterocyclic rings is fused to a benzene ring. The heterocyclic ring may be attached at any heteroatom or carbon atom which results in the creation of a stable structure. Examples of such heterocyclic elements include but are not limited to piperidinyl, piperazinyl, 2-oxopiperazinyl, 2-oxopiperidinyl, 2-oxopyrrolodinyl, 2-oxoazepinyl, azepinyl, pyrrolyl, 4-piperidonyl, pyrrolidinyl, pyrazolyl, pyrazolidinyl, imidazolyl, imidazolinyl, imidazolidinyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, oxazolyl, oxazolidinyl, isoxazolyl, isoxazolidinyl, morpholinyl, thiazolyl, thiazolidinyl, isothiazolyl, quinuclidinyl, isothiazolidinyl, indolyl, quinolinyl, isoquinolinyl, benzimidazolyl, thiadiazoyl, benzopyranyl, benzothiazolyl, benzoxazolyl, furyl, tetrahydrofuryl, tetrahydropyranyl, thienyl, benzothienyl, thiamorpholinyl, thiamorpholinyl sulfoxide, thiamorpholinyl sulfone, and oxadiazolyl.
The pharmaceutically-acceptable salts of the compounds of the present invention (in the form of water-or oil-soluble or dispersible products) include the conventional non-toxic salts or the quaternary ammonium salts which are formed, e.g., from inorganic or organic acids or bases. Examples of such acid addition salts include acetate, adipate, alginate, aspartate, benzenesulfonate, bisulfate, butyrate, citrate, camphorate, camphorsulfonate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, fumarate, glucoheptanoate, glycerophosphate, hemisulfate, heptanoate, hexanoate, hydrochloride, hydrobromide, hydroiodide, 2-hydroxyethanesulfonate, lactate, maleate, methansulfonate, 2-naphthalenesulfonate, nicotinate, oxalate, pamoate, pectinate, persulfate, 3-phenylpropionate, picrate, pivalate, propionate, succinate, tartrate, thiocyanate, tosylate, and undecanoate. Base salts include ammonium salts, alkali metal salts such as sodium and potassium salts, alkaline earth metal salts such as calcium and magnesium salts, salts with organic bases such as dicyclohexylamine salts, N-methyl-D-glucamine, and salts with amino acids such as arginine, lysine, and so forth. Also, the basic nitrogen-containing groups may be quaternized with such agents as lower alkyl halides, such as methyl, ethyl, propyl, and butyl chloride, bromides and iodides; dialkyl sulfates like dimethyl, diethyl, dibutyl; and diamyl sulfates, long chain halides such as decyl, lauryl, myristyl and stearyl chlorides, bromides and iodides, aralkyl halides like benzyl and phenethyl bromides and others.
Synthesis of Noscapine
Noscapine is an alkaloid occurring in abundance in the opium plant, Papaver somniferum L. papaveraceae. It can be extracted from the water-insoluble residue remaining from the processing of opium in the commercial synthesis of morphine. It is readily available commercially in large quantities at low cost, from e.g., Aldrich Chemical Co., or Sigma Chemical Co. Noscapine can be separated from other opium alkaloids by the procedure according to Al-Yuhya, M. A. et al., in K. Florey (Ed.) Analytical Profiles of Drug Substances, Vol. 11 Academic Press 1982, pp. 407-461, or Sim, S. K. xe2x80x9cMedicinal Plant Alkaloids,xe2x80x9d 2nd Ed. Un. Toronto Press 1970, p. 70.
Chemical synthesis of noscapine 1 is less desirable, although feasible. See, for example, Fleischhacker, W. et al. Chem. Monthly 120, 765 (1989); Shono, T. et al. Tetrahedron Lett. 21, 1351 (1980).
There are a variety of methods to synthesize noscapine. A one step synthetic reaction was published by W. H. Perkin and R. Robinson, J. Chem. Soc. [London], 99, 775 (1911). However, this method gave low yield and racemic mixtures. The reaction is shown as follows: 
A second method was published by Von P. Kereks and R. Bognar. J. Prakt. Chem. 313, 923-928 (1971). In this method, 2-(3xe2x80x2-methoxy-4xe2x80x2,5xe2x80x2-methylenedioxy-phenyl) ethylamine 13 reacts with meconine-3-carbonyl chloride 14 in benzene to gove N-(xcex2-3-methoxy-4,5-methylenedioxyphenylethyl)-mekonine-3-carbonylamide 15 with a yield of 86.6%. Compound 15 was cyclized by boiling with POCI3 for 5 hr to produce compounds 16 and 17 with a yield of 46.7%. Compounds 16 and 17 are two isomers from cyclization of compound 15. These two isomers are reduced by either H2/PtO2 in acetic acid, or NaBH4 in methanol. The reduced compound 18 was methylated by boiling with the mixture of HCHO and HCOOH, to produce noscapine 1 with a yield of 20.3%. 
The compounds of the present invention are generally useful in the treatment of tumor cells and a variety of cancers, including but not limited to cancer of the colon, non-small cell lung cancer, cancer of the brain, ovarian cancer, cancer of the kidney, cancer of the prostate, leukemia, breast cancer, skin cancer, melanoma, and cancer of the bladder. For most of these kinds of neoplastic diseases, applicants have tested a variety of cell lines with noscapine, or derivatives thereof. The compounds of the present invention are generally delivered in dosage unit formulations containing conventional non-toxic pharmaceutically-acceptable carriers, adjuvants and vehicles.
One embodiment of the invention relates to the discovery that noscapine has been found to inhibit the progression of melanoma. Specifically, the present inventors have determined that noscapine is effective against tumors derived from malignant melanoma cells, a tumor considered to be refractory to chemotherapy. Noscapine suppresses microtubule dynamics in cells. It increases the pause duration by from about 54% to about 244% and decreases the rate of microtubule shortening by about 20% to about 90%. This treatment procedure led to about an 83% reduction of tumor volume compared to untreated animals. In other words, the present inventors have determined that noscapine, and most likely noscapine derivatives, prevents a number of dynamic events in the life history of a microtubule, without affecting its long term existence, and that noscapine and its derivatives is effective in selectively inhibiting tumor growth.
Without wishing to be bound to any theory, it appears that minor pertubations in microtubule dynamics can engage a mitotic checkpoint, arresting cells in mitosis. The loss of mitotic checkpoints in tumor cells might, in fact, be a very common occurrence associated with cancer. Cells that lack mitotic checkpoints are highly sensitive to mitotic stress caused by microtubule targeting agents, leading to the appreciation that checkpoint loss might contribute positively toward chemotherapeutic outcome for some cancers. See Landen, J. W., et al., Noscapine Alters Microtubule Dynamics in Living Cells and Inhibits the Progression of Melanoma (2001) (unpublished manuscript, on file with Emory University School of Medicine), incorporated herein in its entirety by this reference.
Another embodiment of the invention relates to delivery systems and methods for delivering the compounds of the present invention via a controlled-release mechanism. For example, if the compounds of this invention can be administered via a time-release mechanism or can be altered or modified such that the compound itself is adapted for controlled-release, its activity and therapeutic effect may be prolonged.
In one embodiment, the compounds are delivered via controlled-release mechanisms such as time-release devices. Such controlled-release mechanisms may include, but are not limited to, implantable devices, delivery pumps, wafers, biodegradable polymers, gels, lotions, topical applications, and combinations thereof. For example, implantable devices such as osmotic pumps may be implanted to continuously deliver drugs at controlled rates. Such pumps can be implanted subcutaneously or intraperitoneally, and can be designed for targeted delivery, i.e., to a particular tissue or organ, or for general delivery.
One example of such a pump is the ALZET(copyright) osmotic pump. These pumps are used in the research setting and are implanted into research animals to maintain certain plasma concentrations of a drug at certain levels. Another example of such a pump is the DUROS(copyright) pump. This pump operates like a miniature syringe loaded with a drug inside the drug reservoir. Through osmosis, water from the body is slowly drawn through a semipermeable membrane into the pump by salt residing in the engine compartment. This water fills the pump, which slowly and continuously pushes a piston, dispensing the correct amount of drug out the drug reservoir and into the body. Such osmotic engines do not require batteries, switches or other electromechanical parts in order to operate. The amount of drug delivered by the system is regulated by the membrane""s control over the amount of water entering the pump and by the concentration of the drug in the drug reservoir.
It is preferable that the controlled-release mechanism be adapted to deliver the composition at the desired dosing rate with a high degree of precision. It is also preferable that the system protect the composition from degradation by enzymes and its passage through the body so that the system is not required to be removed and replaced continuously. In most instances, the controlled-release mechanism is placed just under the skin, for example in the upper arm.
Controlled-release mechanisms may be used that are systemic or adapted for site-specific administration of the composition. For example, to deliver a drug to a specific site, the company manufacturing the DUROS(copyright) system is developing miniaturized catheter technology that can be attached to the system to direct the flow of a drug to the target organ, tissue or synthetic medical structure, such as a graft. Site specific delivery enables a therapeutic concentration of a drug to be administered to the desired target without exposing the entire body to a similar dose.
Although specific controlled-release mechanisms have been described, it is understood that any implantable controlled-release mechanisms that can be used to deliver noscapine or its derivatives is considered within the scope of this invention. For example, implantable delivery devices are also currently used in some patients to deliver birth control over an extended period of time. Such implants or similar implantable devices used to deliver noscapine or its derivatives are time-release mechanisms within the scope of this invention.
Another controlled-release mechanism for use with the present invention is a wafer. Wafers can be provided in various sizes and various materials and delivered directly to a surgical cavity. For example, after a tumor has been resected, a wafer may be placed in the resulting cavity. Additionally or alternatively, a wafer may be implanted on or near an area of a tumor. One example of a wafer currently available is the Gliadel(copyright) wafer. This wafer contains carmustine, and up to eight wafers are implanted in a cavity when a brain tumor is surgically removed. The wafer delivers chemotherapy directly to the site of a tumor.
According to various embodiment of the present invention, any number of wafers containing noscapine or its derivatives can be implanted in a surgical cavity, on or near a tumor, or any combination thereof, in order to deliver noscapine or its derivatives to a patient in need thereof. For example, after brain surgery, a wafer containing noscapine or its derivatives may be implanted in the surgical cavity. This may be used in conjunction with other controlled-release mechanisms described herein. Alternatively, after a mastectomy, a wafer containing noscapine or its derivatives may be implanted in the surgical cavity. This concept is envisioned for use during any type of tumor resection.
In an alternate embodiment of the invention, the controlled-release mechanism is a biodegradable matrix or polymer. The composition of this invention can be complexed, mixed with, or otherwise associated with a matrix or polymer that can be injected into or just under a patient""s skin. As the matrix or polymer slowly degrades over time, more and more of the active composition can be released. Examples of such matrixes or polymers are currently known in the art.
In another embodiment of the invention, noscapine or its derivatives is delivered topically, for example, via a gel, a lotion, or a patch. In some aspects, a gel or lotion may be applied topically, i.e., directly to a patient""s skin on or near the site of, for example, a skin tumor. In a preferred embodiment, the gel or lotion has controlled-release beads or capsules contained therein. One skilled in the art would be knowledgeable about how to prepare such compositions. However, even without such beads or capsules, a noscapine or noscapine derivative gel or lotion should be considered a controlled-release mechanism within the scope of this invention: the patient may apply a light layer to the skin or may apply a heavier layer that will take longer to absorb, thus at least partially controlling the release of the composition. Additionally or alternatively, the gel or lotion may be applied orally, rectally, nasally, or combinations thereof.
Another topical application for use with another embodiment of this invention is a noscapine or noscapine derivative patch. The composition may be included in a patch for delivery through the skin. Patches of this type are known in the art any may include additional skin penetrating enhancers.
A further embodiment includes the delivery of noscapine or its derivatives via iontophoresis. Specifically, the number of drugs that may be delivered by the transdermal route is limited by the barrier properties of the skin. Conventional transdermal therapy is traditionally limited to small, potent and lipophilic drugs. Iontophoresis is one strategy that facilitates transdermal drug delivery. Iontophoresis is facilitated movement of ions across a membrane, e.g. the skin in order to deliver a positively charged drug across the skin. In this embodiment, a solution of, for example, a cationic formulation of noscapine or its derivatives may be placed at the positive electrode where it is repelled and then attracted towards a negative electrode place elsewhere on the body.
Additional or alternative controlled-release mechanisms for use with this invention comprise a controlled-release formula of the compound. In other words, the controlled-release mechanism may comprise a modification or alteration of the compound itself. For example, the controlled-release mechanism may comprise caged, protected, or modified forms of noscapine or its derivatives for efficient or enhanced delivery and/or later activation purposes. This embodiment relates to the use of prodrugs in cancer chemotherapy to target relatively toxic compounds to specific areas of pathology. This controlled-release mechanism allows more efficient release of the compound into the specific area of pathology sought to be treated. Two technologies that are particularly relevant to this invention are antibody directed enzyme prodrug therapy (ADEPT) and the use of polymeric prodrugs (commonly known as polymer drug conjugates).
As described by Ijeoma F. Uchegbu, Parenteral drug delivery: 2, PHARMACEUTICAL JOURNAL, Sep. 4, 1999, at 355, incorporated herein by this reference, (also at www.pharmj.com/Editorial/19990904/education/parenteral2.html), the principle behind the ADEPT approach is that an antibody-enzyme conjugate is administered intravenously, localizes in tumor tissue, and subsequently activates an administered prodrug predominantly within such tumors. Prodrug activation occurs on the cell surface or in the extracellular fluid, which is in different from the polymeric prodrug approach, where prodrug activation occurs intracellularly. The appearance of the active drug after prior administration of the antibody-enzyme conjugate to patients confirms the feasibility of the ADEPT approach. In some instances, to promote specificity, a non-human, e.g., bacterial, enzyme such as carboxypeptidase G2 is used to activate the prodrug. Because such enzymes may also elicit an immune response, it may also be necessary to administer an immunosuppressant. Preferably, the prodrug should be nontoxic and the enzyme should locate only at tumor sites. The use of noscapine or its derivatives in conjunction with research in this area to treat neoplastic diseases is considered within the scope of this invention.
This article also describes the use of polymeric prodrugs, which involves the use of an active substance and possibly a targeting moiety, both linked via spacers to a water-soluble polymeric backbone. From this basic configuration, a number of polymer drug conjugates for cancer chemotherapy have been synthesized with cleavable drug polymer linkers.
Polymer drug conjugates accumulate selectively within tumor tissue and leak through the disorganized vasculature. Clearance from tumor tissue is delayed due to the poor lymphatic drainage, thus tumor accumulation of polymer drug conjugates has been called the enhanced permeation and retention effect. On IV administration the conjugate is taken up by tumor cells and the active drug released intracellularly.
Most of the polymeric backbones that have been studied are prepared from non-biodegradable materials. Although in some instances, biodegradable polymers may be more acceptable, care must be taken to ensure that biodegradation does not hamper the accumulation of conjugates in tumor tissue.
The use of polymer drug conjugates is believed to improve the activity of anticancer agents. Polymer drug conjugates also decrease distribution to potential sites of toxicity. By targeting certain compounds away from sites of potential toxicity, polymer conjugates can significantly increase the maximum tolerated dose of a compound in patients. The use of noscapine or its derivatives in conjunction with research in this area to treat neoplastic diseases is considered within the scope of this invention.
In an even further embodiment of this invention, the controlled-release mechanism for noscapine or its derivatives enhances the permeability of the composition through a patient""s blood-brain barrier in order to treat brain tumors. This may be done through any number of methods. Examples include, but are not limited to disruption of the blood brain barrier, receptor-mediated mechanisms, and liposomal encapsulation.
For example, it has been reported that temporarily opening the blood-brain barrier can allow chemotherapeutic agents to pass into the brain and reach the tumor. See, e.g., www.ohsu.edu/hosp-bbb/bbbdtherapy.html. Specifically, the brain""s protective barrier is composed of tightly knit endothelial cells, which line the walls of the blood vessels in the brain. These tightly knit cells create a barrier that blocks the entry of various substances, including many therapeutic agents. By temporarily shrinking these cells with a concentrated sugar solution, the barrier can be opened, allowing chemotherapy drugs, such as noscapine or its derivatives, to pass into the brain and reach the tumor. It has been found that compared with standard chemotherapy, blood-brain barrier disruption therapy increases the delivery of the chemotherapy drugs to the tumor and its surrounding area around the tumor by tenfold to a hundredfold.
Another embodiment includes using peptide drug transporters linked to, or otherwise associated with, noscapine or its derivatives to enhance access to the brain. It has been found that various peptide drug modifications can enhance bioavailability and blood-brain barrier permeability. See, e.g., Ken A. Witt, et al., Peptide Drug Modifications to Enhance Bioavailability and Blood-Brain Barrier Permeability, 22 PEPTIDES 2329 (2001), incorporated herein by reference. This article discusses modifications such as lipidization, structural modification to enhance stability, glycosylation, use of nutrient transporters, prodrugs, vector-based strategies, cationization, and polymer conjugation.
The embodiment related to modifying noscapine or its derivatives by receptor-mediated mechanisms includes altering noscapine or its derivatives or packaging it into an agent that is capable of binding to tumor cell receptors and therefore selectively entering tumor cells. This embodiment would enable researchers to target these agents specifically to tumor cells by drugs with high biological activity and a low incidence of side effects since the drug would only enter cells with appropriate receptors.
The embodiment related to liposomal encapsulation includes noscapine or its derivatives encapsulated liposomally, enabling it to readily permeate lipid rich cell membranes and enhance its delivery to cells. Liposomes are formed by the self-assembly of phospholipid molecules in an aqueous environment. The amphipathic phospholipid molecules form a closed bilayer sphere in an attempt to shield their hydrophilic groups from the aqueous environment, while still maintaining contact with the aqueous phase via the hydrophilic head group. The resulting closed sphere may encapsulate aqueous soluble drugs, such as noscapine or its derivatives, with the bilayer membrane.
Alternatively, lipid soluble drugs may be complexed with cyclodextrines and subsequently encapsulated within the liposome aqueous compartment. Drugs encapsulated within or associated with liposomes in this way alters drug pharamacokinetics and may be useful in various targeted therapies. These concepts may be used in conjunction with noscapine or its derivatives in order to optimize liposomal drug targeting and delivery. For example, the reduced liver and spleen uptake of stealth liposomes (as polyoxyethylene liposomes came to be known) is believed to be due to a reduced coating recognition by the liver and spleen and enjoy long circulation times.
Another embodiment of this invention relates to noscapine or its derivatives modified with tumor specific antibodies, ligands for tumor specific proteins, or as an adduct for the compound or its derivatives for tumor targeting purposes. For example, tumor associated antigens (xe2x80x9cTAAxe2x80x9d) are highly, homogeneously, frequently and selectively expressed on the cell surface in clinical tumor samples and represent potentially excellent targets for tumor immunotherapy. The use of antibodies selective for TAA or other ligands for tumor specific proteins added to noscapine or noscapine derivative structures is believed to enable the precise targeting of those agents to tumor tissue.
In an additional or alternate embodiment, the compounds of the present invention may be delivered in combination with additional, more common, tumor or cancer therapies. For example, noscapine or noscapine derivatives may be used as a preventive measure after surgical excision or in combination with other anti-cancer treatments. For instance, noscapine or its derivatives may be delivered in combination with radiation therapy, phototherapy, surgical resection, immunotherapy, vaccination, interferon treatment, chemotherapy, stereotactic surgery, such as Gamma Knife(copyright) surgery, and combinations thereof. Some classes of chemotherapy include but are limited to: covalent DNA binding drugs, anti-metabolites, anti-tumor antibiotics, microtubule-targeting drugs, DNA-based topoisomerase inhibitors (I and II), differentiation agents, hormonal agents, enzymes, and any combination thereof. Further examples and descriptions are provided in MICHAEL C. PERRY, CHEMOTHERAPY SOURCE BOOK (Williams and Wilkins 2d ed. 1997), incorporated herein by reference.
These treatments are merely provided as examples and are not intended to be exhaustive of the possible cancer treatments available not intended to limit the present invention. It is anticipated the cancer researchers will invent and/or discover other therapies that may be used to treat tumors, and noscapine or its derivatives used in combination with such treatments to treat neoplastic diseases is considered within the scope of this invention.
In a further embodiment, the compounds of the present invention may be administered orally, rectally, nasally (for example, by inhalation spray), parenterally (including subcutaneous injections, intravenous, intramuscular, infrasternal injection or infusion techniques), intraperitoneal delivery, direct tissue injection, topical delivery, and combinations thereof.
These pharmaceutical compositions may be in the form of orally-administrable suspensions or tablets; nasal sprays; sterile injectable preparations, for example, as sterile injectable aqueous or oleaginous suspensions or suppositories.
When administered orally as a suspension, these compositions are prepared according to techniques well-known in the art of pharmaceutical formulation and may contain microcrystalline cellulose for imparting bulk, alginic acid or sodium alginate as a suspending agent, methylcellulose as a viscosity enhancer, and sweeteners/flavoring agents known in the art. As immediate release tablets, these compositions may contain microcrystalline cellulose, dicalcium phosphate, starch, magnesium stearate and lactose and/or other excipients, binders, extenders, disintegrants, diluents and lubricants known in the art.
When administered by nasal aerosol or inhalation, these compositions are prepared according to techniques well-known in the art of pharmaceutical formulation and may be prepared as solutions in saline, employing benzyl alcohol or other suitable preservatives, absorption promoters to enhance bioavailability, fluorocarbons, and/or other solubilizing or dispersing agents known in the art.
The injectable solutions or suspensions may be formulated according to known art, using suitable non-toxic, parenterally-acceptable diluents or solvents, such as mannitol, 1,3-butanediol, water, Ringer""s solution or isotonic sodium chloride solution, or suitable dispersing or wetting and suspending agents, such as sterile, bland, fixed oils, including synthetic mono-or diglycerides, and fatty acids, including oleic acid.
When rectally administered in the form of suppositories, these compositions may be prepared by mixing the drug with a suitable non-irritating excipient, such as cocoa butter, synthetic glyceride esters or polyethylene glycols, which are solid at ordinary temperatures, but liquidity and/or dissolve in the rectal cavity to release the drug.
When delivered as a topical formula, the compositions may be prepared with any gel or lotion substrate commonly known in the field of topical drug delivery. Such preparations would be apparent to those of skill in the art.
Thus, in accordance with the present invention there is further provided a method of treating and a pharmaceutical composition for treating tumor cells and related cancers. The treatment involves administering to a patient in need of such treatment a pharmaceutical composition comprising a pharmaceutical carrier and a therapeutically effective amount of a compound of the present invention, or a pharmaceutically acceptable salt thereof.
Doses and dosage levels will vary depending upon the state of the condition treated, the delivery route chosen, and other physical considerations. In one embodiment, dosage may range of the order of 0.02 to 5.0 or 10.0 grams-per-day, which has been found useful in the treatment or prevention of the above-indicated conditions, with oral doses two-to-five times higher. For example, compound 4 is effectively treated by the administration of from 10 to 50 milligrams of the compound per kilogram of body weight from one to three times per day.
It will be understood, however, that the specific dose level and frequency of dosage for any particular patient may be varied and will depend upon a variety of factors including the activity of the specific compound employed, the metabolic stability and length of action of that compound, the age, body weight, general health, sex, diet, mode and time of administration, rate of excretion, drug combination, the severity of the particular condition, and the host undergoing therapy.